Applied since Middle English to other short metal rods (especially those with knobbed ends). From the notion of an arrow's flight comes the lightning bolt (1530s). A bolt of canvas (c.1400) was so called for its shape. Adverbial phrase bolt upright is from late 14c.

Example Sentences forbolt upright

Surefoot, bolt upright on the topmost bend, was leading the chorus.

Miss Walbrook let the paper fall, sat bolt upright, and listened.

Her head was slightly bent, but the rest of her young figure was bolt upright.

There was an urgency in the sound that brought him bolt upright from his pillow in alarm.

She was bolt upright herself, and wrath flamed in her own eyes.

The girl stared, breathless, astounded, bolt upright in her saddle.

At Welton's invitation he sat, but bolt upright at the edge of a chair.

In the back parlor six pallbearers sit upon chairs, all of them bolt upright, with their hands on their knees.

Slowly he drew up a chair to where Amory sat, bolt upright and robed in her consciousness of rectitude, on the sofa.